Identify the form of the verb.
D. Progressive.
The sentence presents a verb in the progressive form, which is an action that is taking place in the present and is formed by the basic form of the verb "work" plus "ing": working.
The sentence with a basic form of the verb would be:
- I work on my homework for hours.
The sentence with a emphatic form ("do" plus present or past form of the verb):
- I do work on my homework for hours.
"Work" is a regular verb, thereby, it cannot be used as an irregular one. It can be changed thus:
- I have written on my notebook for hours.